Design and Analysis of a Novel Low-Power SRAM Bit-Cell Structure at Deep-Sub-Micron CMOS Technology for Mobile Multimedia Applications

Abstract

The growing demand for high density VLSI circuits and the exponential dependency of the leakage current on the oxide thickness is becoming a major challenge in deep-sub-micron CMOS technology. In this work, a novel Static Random Access Memory (SRAM) Cell is proposed targeting to reduce the overall power requirements, i.e., dynamic and standby power in the existing dual-bit-line architecture. The active power is reduced by reducing the supply voltage when the memory is functional and the standby power is reduced by reducing the gate and sub-threshold leakage currents when the memory is idle. This paper explored an integrated approach at the architecture and circuit level to reduce the leakage power dissipation while maintaining high performance in deep-submicron cache memories. The proposed memory bit-cell makes use of the pMOS pass transistors to lower the gate leakage currents while full-supply body-biasing scheme is used to reduce the sub-threshold leakage currents. To further reduce the leakage current, the stacking effect is used by switching off the stack transistors when the memory is ideal. In comparison to the conventional 6T SRAM bit-cell, the total leakage power is reduced by 50% while the cell is storing data ‘1’ and 46% when data ‘0’ at a very small area penalty. The total active power reduction is achieved by 89% when cell is storing data 0 or 1. The design simulation work was performed on the deep-sub-micron CMOS technology, the 45nm, at 250C with VDD of 0.7V.